Phlegm Color: What Does It Mean?

Phlegm color can change when you're ill or exposed to smoke and pollution.

Normal phlegm is clear. When bacteria, viruses, or foreign substances invade the respiratory system and collect in the phlegm, it may thicken and alter in appearance.

Discolored phlegm related to fighting a minor infection or allergies, will usually clear on its own or with at-home treatment. Dark phlegm and unusual discharge may mean you need to see a healthcare provider for prescription medication or more significant treatment.

Yellow Phlegm

Heavy phlegm that's pale yellow or cloudy white may be related to allergies or asthma. It can also be a sign of a minor infection.

Allergens and irritants trigger your body to build up the mucus in your nasal passages. As the phlegm accumulates, it may cause a runny nose. The excess mucus will also likely run down the back of your throat (post-nasal drip), causing a cough.

For both asthma and allergies, you can prevent symptoms by avoiding triggers. Allergy symptoms may be treated with over-the-counter antihistamines or prescription medication when needed.

For immediate relief, use saline nasal rinses to thin out phlegm.

Green Phlegm

Phlegm related to an infection can start out yellow but may become a darker green. The color change happens when there are a lot of white blood cells and other debris in the mucus.

A darker green color is commonly a result of a bacterial infection. If your symptoms last for several days and include a fever or sinus pain, see a healthcare provider. While green phlegm may be a sign you need an oral antibiotic to treat an infection of the chest or respiratory system, a proper diagnosis is required to confirm this.

Red Phlegm

Bright red or dark red phlegm is also called hemoptoic sputum. Bright red phlegm usually means there's fresh blood in the airway while dark red phlegm means the blood is older.

Common causes of blood in phlegm include:

• Acute respiratory infections such as the common cold, pharyngitis (inflammation of the throat), epiglottitis (swelling of the epiglottis), and inflammation of the larynx
• Cancer
• Bronchiectasis
• Chronic obstructive pulmonary disease (COPD)

In more than 90% of cases, the symptoms are mild and go away on their own.

Pink Phlegm

Phlegm that is pink and frothy can be a sign of pulmonary edema. Sometimes called "wet lung," pulmonary edema, is a serious medical condition that occurs when the air sacs of the lung (alveoli) fill with fluid.

People who experience pulmonary edema say it feels like drowning as they struggle to breathe and get enough oxygen.

Pulmonary edema requires immediate medical treatment to remove fluid from the lungs and relieve pressure on the heart. Long-term care focuses on healing the underlying cause of the fluid buildup.

Brown Phlegm

Brown phlegm is often a sign of chronic lung disease. It's usually caused by a buildup of bacteria and blood in the lungs that change the thickness and color of the phlegm.

Lung infections that cause brown phlegm include COPD and emphysema.

Treating these conditions may allow you to manage the phlegm. Your healthcare provider will help you determine the right options, which may include medications, inhalers, supplemental oxygen, or surgery.

In some instances, dark brown expectoration can be the result of a fungal infection in the lungs. This requires antifungal therapies to clear the infection.

Black Phlegm

Black or gray phlegm is also called melanoptysis. This is a very rare occurrence. The underlying causes may include the following:

• Cigarette smoking
• Exposure to dust
• Pneumoconiosis (often the result of coal dust exposure)
  
• Fungal infection

Your risk of developing black phlegm is greater if you're immunocompromised due to other illnesses such as cancer.

See a healthcare provider anytime you cough up black-colored mucus.

Summary

Phlegm is one important type of mucus that plays a role in the normal functioning of your airways.

Changes in the normal clear color of phlegm may indicate an illness or exposure to irritants. Viral, bacterial, and fungal infections along with allergies and smoking can alter the consistency and shade of phlegm that you cough up or blow from your nose.

See a healthcare provider if discolored phlegm lasts for more than a few days or is accompanied by other signs of an infection. For black or brown phlegm, see your provider right away.